Verapamil but not nifedipine impairs left ventricular function during exercise in hypertensive patients

Can we identify those at risk for a nondiagnostic treadmill test in a chest pain observation unit?

BACKGROUND

Exercise treadmill testing (ETT) is a testing modality that has shown to be a useful chest pain observation unit (CPU). One limitation of this tool is the high rate of nondiagnostic tests. We aim to create a predictive model to discriminate a patient's risk for a nondiagnostic test.

METHODS

This is a retrospective analysis of consecutive subjects admitted to our CPU and undergoing an ETT from January 2001 to December 2006. To account for any variation in physician practice, the training set was those patients admitted January 2004 to December 2006 and the testing set comprised those evaluated January 2001 to December 2003. Recursive partitioning with 10-fold cross validation was used to identify significant variables associated with the outcome measure of a nondiagnostic treadmill test. The beta coefficient from the regression model was used to create a risk score. This risk score was then used stratify patients.

RESULTS

A total of 1708 subjects underwent ETT during the study period. The training set comprised 408 subjects with 62 having a nondiagnostic test. Logistic regression identified age, prior history of coronary artery disease, smoking, and diabetes variables used to create a scoring system. The testing set identified 387 (29.7) subjects meeting our criteria as low risk (9.0%) nondiagnostic test and identified 298 (22.9%) at high risk for a nondiagnostic test (32.8%).

CONCLUSION

Using a simple scoring system to stratify patients undergoing ETT into 3 risk groups, we were able to identify a low-risk group <10% and a high-risk group >30% for having a nondiagnostic ETT.

Chest Pain Units: Management of Special Populations

Chest pain units provide an important alternative to traditional hospital admission for patients who present to the emergency department with symptoms compatible with acute coronary syndrome and a normal or inconclusive initial evaluation. Although patient subgroups such as women, diabetics, those with established coronary artery disease,and those with symptoms related to stimulant use present unique challenges,management in a chest pain unit appears to be appropriate in these populations. Judicious application of accelerated diagnostic protocols and current testing methods can promote safe, accurate, and cost-effective risk stratification of special populations to identify patients who can be safely discharged and patients who require hospital admission for further evaluation.

Functional Imaging for the Monitoring of Clinical Outcomes of Pharmacotherapy

Functional and anatomic imaging have been used almost exclusively for diagnostic purposes. Because pharmacotherapy is expected to alter organ function, functional imaging is ideally suited to assess drug effects. The application of functional imaging techniques for this purpose has recently emerged. This paper reviews application of radiopharmaceuticals and nuclear imaging techniques to the assessment of pharmacologic effects in neurology, psychiatry, cardiology, and oncology.

Verapamil and nifedipine in combination for the treatment of hypertension

The authors examined the efficacy and safety of the combination of verapamil and nifedipine in the control of hypertension. Retrospective analysis of blood pressures was obtained on 50 patients who had historically documented essential hypertension and were receiving verapamil and nifedipine. The patients had moderate to severe hypertension; 27 of 50 (54%) were uncontrolled on prescribed regimens of two or more separate classes of drugs. Control was defined by the ability to maintain a blood pressure of < or = 160/90 by providing doses of verapamil (max: 480 mg/day) and nifedipine (max: 180 mg/day). Twenty-nine (58%) were black and 21 (42%) were white. Ages ranged from 16 to 84 years. Mean duration of therapy was 1-2 years. Only 3 of 50 (6%) were control failures after providing verapamil and nifedipine. Three of 50 (6%) were discontinued because of side effects--reversible hepatitis (2) and rash (1). There were no serious adverse events, i.e., CHF or arrhythmias. Manageable ankle edema was seen in 14 of 50 (28%) patients. Verapamil and nifedipine, a combination of a dihydropyridine and a non-dihydropyridine calcium antagonist, was effective and safe in this group of patients with difficult-to-manage hypertension.